Quality Assurance Flashcards
7 cards from real SE ENGR. practice questions. Tap to flip, then mark Knew It or Still Learning โ missed cards come back until you master them.
Read the first 7 Quality Assurance flashcards as text
Under IEC 62446-1, which test is part of the Category 1 commissioning sequence for all PV systems?
Answer: Insulation resistance of array circuits
Category 1 includes protective earth continuity, polarity, string Voc/Isc, functional tests, and insulation resistance.
What is the main reason module manufacturers specify a positive-only power tolerance such as 0/+5 W?
Answer: To guarantee flash-tested power is never below nameplate rating
Positive-only tolerance assures buyers each module delivers at least its nameplate STC power.
Snail trails visible on installed modules are most commonly associated with which underlying condition?
Answer: Cell microcracks combined with a reaction of silver paste and encapsulant
Snail trails form along microcracks where moisture and encapsulant additives react with silver fingers, causing discoloration.
Light-induced degradation (LID) in conventional p-type Czochralski silicon cells is primarily caused by which mechanism?
Answer: Boron-oxygen complex formation
Boron-oxygen defects form under initial light exposure in p-type Cz silicon, reducing carrier lifetime.
Which certification standard addresses grid-support functions so that US inverters can demonstrate IEEE 1547-2018 compliance?
Answer: UL 1741 SB
UL 1741 Supplement SB tests inverters against IEEE 1547.1-2020 for IEEE 1547-2018 grid-support compliance.
A control chart of daily string inverter efficiency shows seven consecutive points above the centerline, all within control limits. What should a QA engineer conclude?
Answer: A non-random shift has likely occurred and should be investigated
Run rules flag long runs on one side of the centerline as a likely special-cause shift even within limits.
Why must irradiance and module temperature be recorded alongside field I-V curve measurements?
Answer: To translate measured values to STC for comparison with datasheet ratings
Field I-V data must be corrected to STC using irradiance and cell temperature to compare with rated performance.